1. Field of Inventions
The present inventions relate generally to devices for performing therapeutic operations on body tissue.
2. Description of the Related Art
There are many instances where therapeutic elements must be positioned adjacent to body tissue. One instance involves the formation of therapeutic lesions to treat cardiac conditions such as atrial fibrillation, atrial flutter and arrhythmia. Therapeutic lesions, which may also be used to treat conditions in other regions of the body such as the prostate, liver, brain, gall bladder, uterus, breasts, lungs and other solid organs, are typically formed by ablating tissue.
The present inventor has determined that lesion formation devices are susceptible to improvement. For example, the present inventor has determined that conventional lesion formation devices can be difficult to position and can damage non-target tissue near the tissue in which the therapeutic lesions are being formed. Conventional lesion formation apparatus can also roll in the direction of non-target tissue after being properly positioned. In the context of epicardial pulmonary vein isolation, it is desirable to form lesions in cardiac tissue because ablation of the pulmonary veins or pulmonary vein ostia can lead to stenosis. The present inventor has also determined that it would be desirable to provide devices that more accurately focus tissue coagulation energy during a lesion formation procedure in order to enhance the therapeutic effect, increase efficiency, and reduce the likelihood that non-target tissue will be ablated.